Method and apparatus for convolutely winding tubes of irregular shapes

ABSTRACT

Multi-ply tubular members of non-circular cross sectional shape are convolutely wound of sheet material on a mandrel of the desired non-circular shape. Improved high bond strength is obtained by continuously pressing the sheet against the mandrel and wound plies during winding and by maintaining the sheet under tension as it is wound. A presser roll, biased against the mandrel and wound plies, is irregularly shaped to follow the contour of the mandrel and wound sheet without oscillation. The presser roll is rotated at an angular velocity that varies relative to that of the mandrel, in accordance with the change in the radii of the mandrel and roll at the pressure line between the two, to establish equal surface velocities. Movement of the unwound portion of the sheet during winding is resisted by a vacuum table on which the sheet is supported. Quick-setting adhesives are applied to the sheet just prior to winding by a spray system or quasi-spray system.

United States Patent Gardner [54] METHOD AND APPARATUS FOR CONVOLUTELYWINDING TUBES OF IRREGULAR SHAPES [72] Inventor: Roland C. Gardner, BayVillage, Ohio [73] Assignee: Clevepak Corporation, Cleveland, Ohio [22]Filed: Jan. 8, 1971 [21] Appl. No.2 104,997

[451 May 30, 1972 3,328,219 6/1967 Cupery ..156/446X 3,580,146 5/1971Biancamaria ..93/36MM Primary Examiner-Wayne A. Morse, Jr.Attorneywatts, Hoffmann, Fisher & Heinke 57] ABSTRACT Multi-ply tubularmembers of non-circular cross sectional shape are convolutely wound ofsheet material on a mandrel of the desired non-circular shape. lmprovedhigh bond strength is obtained by continuously pressing the sheetagainst the mandrel and wound plies during winding and by maintainingthe sheet under tension as it is wound. A presser roll, biased againstthe mandrel and wound plies, is irregularly shaped to follow the contourof the mandrel and wound sheet without oscillation. The presser roll isrotated at an angular velocity that varies relative to that of themandrel, in accordance with the change in the radii of the mandrel androll at the pressure line between the two, to establish equal surfacevelocities. Movement of the unwound portion of the sheet during windingis resisted by a vacuum table on which the sheet is supported.Quick-setting adhesives are applied to the sheet just prior to windingby a spray system or quasi-spray system.

1 1 Claims, 10 Drawing Figures Patented May 30-; 1972 4 Sheets-Sheet 11N VENTOR. QOLAND c. GARDNER I oll 5, W mm 5 day M ATTOENEYE WIZ F rg. 3I I I04 75 I, n I mr 76 50 Fig. 4

INVENTOR. POLAND c. emu/-52 BY V//////////// /////////////////A v mmATTOEA/EYE Patented May 30, 1972 4 Sheets-Sheet 5 ANGULAR DISPLACEMENTD/AGQAM FOR PQE55EI? INVENTOR. POLAND C. GHEDNEP BY WM ATTOEUEYSPatented May 30, 1972 3,665,819

4 Sheets-Sheet 4 Fig. I0 I INVENTOR. EULA/KID C. GAEDNEE QTTUENEK?METHOD AND APPARATUS FOR CONVOLUTELY WINDING TUBES OF IRREGULAR SHAPESBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to convolute winding of tubes noncircular in cross sectionalshape.

2. Description of the Prior Art In the convolute winding of tubes fromsheet material it is conventional to press the sheet against the mandreland previously woundconvolutions during winding. Typically, this isaccomplished with a follower roll. Where the mandrel is not cylindrical,the follower ro'll must reciprocate toward and away from the axis of themandrel during winding to follow the irregular contour of the mandreland tube. This may be accomplished by merely biasing the follower rolltoward the mandrel or by utilizing a cam operated linkage synchronizedwith the mandrel rotation. While these methods may operate satisfactoryat low production rates on non-round sections, the radial inertia forcesdeveloped on the follower roll at high winding speeds and highproduction rates become a limiting factor in obtaining satisfactory rollpressure. This is especially true on shapes very non-circular, such astriangular cross sectional shapes. Where insufficient pressure isexerted against the convolutions during winding, the resultinglaminations are not suitably adhered or bonded, and the .tube will havelow bond strength and a shape that departs from that desired.

SUMMARY OF THE INVENTION The present invention overcomes the drawbackssuffered when known winding techniques are used in high speed windingoperations with irregular shapes. In accordance with this invention arotatable presser roll is used, of a shape that exerts continuouspressure on the mandrel or windings, but which eliminates the need forthe roll to reciprocate toward and away from the mandrel duringrotation. To this end, the presser roll is shaped so that when it isdriven in an opposite direction from the mandrel in a predeterminedtimed relationship from a predetermined initial relationship, thecombined distances from the center of rotation of each to the line ofcontact remains constant. The particular contour of the presser rollmaintains the combined distances constant when the rotational speeds ofthe roll and mandrel are unequal to a prescribed extent in a selectedtimed relationship that establishes equal surface speeds at the pressureline between the mandrel and presser roll. Thus, as the relative radialdistances of the roll and mandrel change, from axis to surface, therelative speed of rotation is changed. More specifically, as the radiusof the roll decreases relative to that of the mandrel, the relativerotational speed increases in direct proportion to accurately compensatefor the inherent decrease in surface speed that would occur at aconstant angular velocity. By virtue of the present presser rollconstruction and drive, not only are inertia forces of the typepreviously encountered avoided and a constant, substantially uniform,pressure maintained against the convolutions of the sheet, but also anytendency of the presser roll to reduce the winding tension duringportions of its contact with the convolutions, due to a difference insurface velocity, is minimized or avoided. As a result, the interplybonding and the ability of the wound tube to retain its shape aresubstantially enhanced. In addition, separate cover plies, such aslabels, which are normally thin and difficult to tension during windingand extremely susceptible to wrinkling, canbe smoothly applied toirregular shapes.

In the preferred embodiment, the mandrel and presser roll are eachrotated through 360 cycles of equal time duration. The mandrel is drivenat a substantially constant angular velocity and the variation inrotational speed between the mandrel and roll during each cycle isestablished through the presser roll in timed relationship to therotation of the mandrel. A varying rotational speed of the presser rollis suitably accomplished by driving the roll from the mandrel drivethrough a phase changer. A differential mechanism that varies therotational speed of an output shaft relative to that of an input shaftunder the control of a cam rotated at a constant angular velocity willsuitably accomplish the required continuous phase shifting function. Thecam of predetermined shape and driven from the mandrel drive, causes thedifferential mechanism to change the pressure roll speed in a cyclicalfashion coordinated with the variation in the radius of the roll at thepressure line with the mandrel.

Interply bonding and shape retention are further improved by maintainingthe sheet under tension as it is wound on the mandrel. This isaccomplished in the preferred embodiment of the invention by the use ofa vacuum box or table against which the sheet is held by ambientpressure that retards movement of the sheet toward the mandrel duringwinding.

Additional improvement in the interply bonding and shape retention ofthe tube is obtained through the use of hot melt or other quick-settingadhesives. The use of such adhesives is made practical in the presentinvention by substantially reducing the comparatively long time intervalbetween adhesive application and winding that exists in conventionaltransfer roll or metering bar systems, in which the adhesive is appliedto a web prior to the cutting of a sheet to the required length forwinding. This time reduction is attained by applying the adhesiveuniformly and rapidly to a cut length of sheet material with a spraysystem or quasi spray system just before or as the sheet is convolutelywound. The quick-setting adhesive results in the immediate developmentof the interply bond of the convolutely wound tube to materially improvethe interply bond strength and shape retention already enhanced by thepresser and by the tension under which the sheet is wound.

Accordingly, it is a principal object of this invention to provide animproved method and apparatus for convolutely winding tubes ofnon-circular cross sectional shape, which permit high production ratesand provide improved interply bonding and shape retention. It is a moreparticular object of this invention to provide an improved windingapparatus in which a presser roll is shaped to maintain continuouscontact and pressure against a tube being wound on a mandrel when theroll is rotated at a varying angular velocity relative to the tube andmandrel to establish equal surface velocities of the mandrel and roll ata line of pressure on the sheet or tube between the presser roll andmandrel. It is a further object of this invention to provide a method ofconvolutely winding a tube and to provide winding apparatus of the typereferred to, in which the presser roll is rotated at a varying angularvelocity relative to that of the mandrel, that establishes a surfacevelocity equal to that of the mandrel at the line of pressure on thesheet or tube between the presser roll and mandrel. Other objects,features and advantages of this invention will become apparent from thedetailed description that follows, when considered in connection withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of windingapparatus embodying the present invention;

FIG. 2 is a transverse sectional view taken along the line 2- 2 in FIG.1;

FIG. 3 is a sectional view taken along the line 3-3 in FIG.

FIG. 4 is a transverse sectional view taken along the line 4- 4 in FIG.1;

FIG. 5 is a diagram showing the relative angular displacement of thepresser roll and mandrel with respect to time;

FIGS. 6 to 9 are diagrams showing a triangular mandrel and a presserroll in four different stages of relative rotation, illustrating themanner in which the parts cooperate and the relative degree of rotationat the different stages shown; and

FIG. 10 is a diagram similar to FIG. 9, illustrating a change in spacingbetween the mandrel and the presser ro ll after the winding of a sheet.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Apparatus embodying thepresent invention, for convolutely winding tubes of non-cylindricalcross sectional shape from a sheet of material, such as paper, is shownillustratively in FIGS. 1 to 4. The basic apparatus comprises asupporting structure 10, a winding mandrel 12, a presser roll 14, avacuum table 16, and a spray or quasi-spray adhesive applicator 17. Thewinding mandrel, presser roll, vacuum table and adhesive applicator aresupported by the structure 10. The winding mandrel 12 is an elongatedmember, rotatably driven about its longitudinal axis, for convolutelywinding a sheet S of paper or the like into a tube that corresponds inshape to the cross sectional shape of the mandrel. The presser roll isan elongated roll supported parallel to and adjacent the windingmandrel, for applying pressure to convolutions of the sheet S, as thesheet is wound. The cross sectional shape of the roll eliminates theneed for it to reciprocate relative to the mandrel during the winding ofa sheet. The vacuum table 16 serves as a support for the sheet S priorto winding, and causes the sheet to be tensioned during the winding. Theadhesive applicator 17 is an elongated dispenser that sprays or depositsa thin, substantially uniform, coating of quick-setting adhesive on theupwardfacing surface of the sheet S as or just before it is wound ontothe mandrel. Any suitable dispenser of this type may be used. As shownin FIG. 1, the applicator 17 extends across the width of the sheet Sjust ahead of the mandrel 12, transverse to the direction in which thesheet travels during winding. The applicator is supported for adjustmentalong the direction the sheet moves during winding to vary its positionrelative to the mandrel. This adjustment assures that the applicator canbe accurately positioned so that adhesive is applied only to portions ofthe sheet that form convolutions subsequent to the first, which is indirect contact with the mandrel.

Typically, when a sheet is to be wound into a tube, it is cut to lengthfrom a roll and one end of the sheet is placed into a slot of themandrel l2 and securely gripped while the body of the sheet is supportedon the vacuum table 16. The mandrel is then rotated to wind the sheetabout the mandrel and a suitable quick-setting adhesive is applied tothe upper surface of the sheet, except for the area that will form thefirst convolu tion. The movement of the sheet toward the mandrel duringwinding is retarded by the ambient pressure on the sheet, due to thepressure differential created by the vacuum table. Each convolution ofthe sheet is pressed against the mandrel 12 or preceding convolution bythe pressure roll 14, to adhere each convolution to the next and to becertain that the convolutions follow the contour of the mandrel.

In the particular embodiment shown, the winding mandrel 12 is triangularin cross section, with rounded comers. In this preferred embodiment, thecross sectional shape of the mandrel is a right-isosceles trianglehaving two sides 18a, 18b of equal length and a hypotenuse 180. Thesides 18a, b, c are joined by rounded corner portions 19a, b, c. Alongitudinal slot 21 extends along the length of the mandrel, in theside 18a, and inwardly toward the central axis of the mandrel, which isindicated at A. The slot 21 is adapted to receive an end of the sheet S.The mandrel is provided with a clamping jaw 22 that is spring biased toa closed or clamping position and which is automatically closed andopened at the beginning and end of each winding cycle, in a mannerconventional to winding mandrels.

The mandrel 12 is supported horizontally at opposite ends for rotationabout its longitudinal axis A, with the location of the axis fixedrelative to the supporting structure 10. To facilitate different shapedmandrels and the operation of the clamping jaw 22, the mandrel issupported at each end by rotating head mechanisms, one head mechanism 24being shown in FIGS. 1 and 2, supported on a rotatable spindle 26 by abearing block 28. The spindle 26 is rotatably driven by a varies theangular velocity of the presser roll, as will be described subsequently.

In the preferred embodiment, the mandrel 12 is more than double thelength of the tube to be wound, affording a mandrel portion along whichthe tube can be slid axially after winding, for curing. After the tubeis moved axially, as by an axially movable finger (not shown) thatengages one end of the tube, heated pressure plates (not shown) can beapplied against the outside surface of the tube to cure the adhesivethat bonds the convolutions. This occurs while the mandrel isstationary, preferably during the time a new sheet is fed to themandrel, for winding.

The presser roll 14 is supported horizontally above the mandrel 12, withits central longitudinal axis B parallel to the axis A of the mandrel.In the embodiment shown, the presser roll has three lobes 40, 41, 42.The shape of the roll will be described in more detail in connectionwith FIGS. 6 9. The presser roll 14 is supported at opposite ends forrotation about the axis B by two stud shafts 44, 45, each of which isjoumaled in a forwardly extending portion of a pivoted presser arm 48,49. The stud shaft 44 extends through the presser arm 48 and supports atoothed pulley wheel 52 on its distal end. The pulley wheel 52, shaft 44and presser roll 14 are in fixed relationship so that rotation of thepulley wheel drives the presser roll about the axis B. Each presser arm48, 49 has a bifurcated end 480, 49a, respectively, that straddles asupport pedestal 54, 55, respectively, and each is supported on a hollowpivot shaft 58, 59 that projects from opposite sides of the respectivepedestal 54, 55. The pedestals, in turn, are secured to the supportstructure 10. A pin 60 extends through the bifurcated end 48a of thepresser arm 48 and pivotally connects the presser arm to the end of avertically disposed piston rod 61. The piston rod 61 extends upward froma double-acting fluid-actuated cylinder 62, pivotally supported at itslower end to the supporting structure 10. Similarly, a pin 65 in thebifurcated end 49a of the presser arm 49 connects the arm to the end ofa piston rod 66 from a double-acting fluid cylinder 67 secured to thesupporting structure 10. The fluid cylinders 62 and 67 can be operatedto withdraw the piston rods and thereby pivot the presser arms and liftthe presser roll 14 from the mandrel 12, for example, during the removalof a wound tube. During a winding operation fluid pressure is applied toextend the piston rods to yieldably bias the presser roll 14 against themandrel 12 and the convolutions formed from the sheet being wound.

The presser roll 14 is driven from the drive shaft 37, the controlmechanism 38 and a shaft 70 driven by the mechanism 38. The shafts 37and 70 extend through the hollow pivot shafts 58, 59, respectively, inthe pedestals 54, 55. A toothed pulley wheel 71 is secured to theextending end of the shaft 70, fixed against relative rotation. A timingbelt 72 connects the pulley wheel 71 with the pulley wheel 52, so thatthe anus 48, 49 can pivot and rotation of the drive shaft 37 will drivethe presser roll 14. The pulley wheels 71 and 52 are of equal size, asare the gears 30, 31. Thus, when the shafts 32 and 37 are driven at aparticular rotational speed, the presser roll 14 and the winding mandrel12 are driven at such speeds. By virtue of the mechanism 38, thedirection of rotation of the presser roll is opposite to that of themandrel when the shafts 32, 37 are driven in the same direction, and theangular velocity or rotational speed of the presser roll 14 is variedrelative to that of the mandrel during each complete revolution of bothto provide equal surface or peripheral velocities of the presser rolland mandrel at the line of mutual contact. The variation in rotationalspeed of the shaft 70 is in direct relationship to the change in theradius of the roll relative to that of the mandrel at the line ofcontact. In the preferred embodiment, this change in speed isaccomplished through a continuous phase shifting produced by thedifferential mechanism 38. The driven shaft 37 drives, through acoupling 73, an input shaft 74 that is joumaled in a stationary housing75 supported by the structure (FIGS. 1 and 4). The input shaft 74 has afixed bevel gear 76 that drives another bevel gear 77 on the end of analigned output shaft 78, joumaled in housing 75, through pinions 79freely rotatable in a casing 80 rotatably supported by the shafts 74,78. The output shaft 78 is connected by a coupling 81 to the shaft 70.Thus, when the casing 80 is stationary, the shafts 78 and 70 are drivenby the shafts 37 and 74 in an opposite direction therefrom but at thesame speed. During any rotation of the casing 80, the rotational speedof the shafts 78 and 70 will be slower or faster than that of the shafts37 and 74, depending upon the direction of easing rotation.

A reciprocable rack 84 extends within the housing 75 in a guidway 85,and meshes with a spur gear 87 fixed to the basing 80. The rack extendsout of the housing and is biased outwardly by a compression spring 88.The rack carries a cam 92 fixed to a rotatable shaft 93 supported bybearing blocks 94, 95 on the support structure 10. The shaft 93 and cam92 are rotated by a toothed pulley wheel 97 driven by a timing belt 98from a toothed pulley wheel 99 of the same size fixed to the shaft 37.Depending upon the shape of the cam 92, the rack is reciprocated tovarying extents and at varying rates in timed relationship to therotation of the shaft 37, which is driven at the same speed as themandrel. Accordingly, the presser roll rotational speed will be variedrelative to the mandrel speed by the cam 92. The shape of the cam 92used with the presser roll and mandrel 12, shown, is such that the speedof the presser roll varies relative to that of the mandrel in therelationship shown in FIG. 5, which will be referred to in more detailin connection with FIGS. 6 to 9.

A specific shape of a winding mandrel 12 and a presser roll 14 forwinding a right-isosceles triangular-shaped tube is shown in detail inFIGS. 6 to 9 of the drawings, which also illustrate the manner in whichthe presser roll coacts with the mandrel to maintain surface contactduring winding of a sheet about the mandrel, through l80 of rotation.FIGS. 6 to 9 show four progressive positions, beginning at a point ofcontact between the mandrel and presser roll at the center of thehypotenuse 180 of the mandrel, and ending at the right angle apex 19a,opposite the hypotenuse. For illustrative purposes, increments ofcorresponding peripheral distances about the perimeters of the mandreland presser roll through I80 are indicated by imaginary lines CI to C17radiating from the central axis A of the mandrel and by imaginary linesD1 to D17 radiating from the central axis B of the presser roll. It willbe readily apparent from FIGS. 6 and 9 that the perimeters of themandrel and presser roll are equal. It will also be evident that thedistances from the axes A and B to the respective surfaces of themandrel and presser roll along the different imaginary lines C and Dvaries, and in any fixed plane, such as the imaginary plane P, thatpasses through or contains the axis A of the mandrel and the axis B ofthe presser roll, the actual radial distance of the mandrel surface fromits axis and the presser roll surface from its axis will continuallychange during rotation of the two. The radial dimension is smallest forthe mandrel along the lines indicated C1 and C12, and is greatest at theline C7 that bisects the corner 19d. Conversely, the radial dimension ofthe presser roll is largest along the lines D1 and D12 and smallestalong the line D7. Thus, it will be understood that the surface profileof the presser roll 14 varies in distance from the axis B inversely fromthat of the mandrel, with rotational displacement in an oppositedirection from that of the mandrel, when in the relationship depicted.

As will be appreciated from the different degrees of rotation shown inFIGS. 6 to 9, in which the positions of the axes A and B have notchanged, the sum of the distance from the axis A to the surface of themandrel 12 and the distance from the axis B to the surface of thepresser roll 14, at equal peripheral distances from the reference linesC1 and D1, is constant. As a result, when the mandrel l2 and roll 14 arerotated about their respective axes at essentially equal peripheralspeeds in opposite rotational directions, the surfaces can be maintainedin contact without relative movement of the axes.

Considering the diagram of FIG. 5 along with FIGS. 6 to 8, it can beseen that the rotational speed of the presser roll is varied relative tothat of the mandrel in order to maintain equal peripheral velocities.The curves identified as Presser Roll" and Mandrel" in FIG. 5 show theangular displacement of each in degrees at increments of a given cycletime I during which both are rotated 360. The relative angularvelocities of the two at any given time are indicated by the slope ofeach curve.

Each of the four positions illustrated in FIGS. 6 to 9 is indicated onthe diagram of FIG. 5, at F6, F7, F8 and F9 respectively. FIG. 6 istaken as a reference position of zero displacement. The mandrel 12 isrotated at a constant velocity throughout each cycle, ignoring start upacceleration. The generally slower, then faster, then slower, presserroll speed through 180 displacement is readily apparent from the curves,as. are the positions of equal angular displacement, indicated by thecurve intersections.

In the FIG. 7 position, while the peripheries of the mandrel and presserroll have moved equal distances, as shown by the aligned lines C7 and D7in the plane P, the mandrel has rotated approximately 65 and the presserroll approximately 72, as shown both in FIG. 7 and the displacementdiagram of FIG. 5.

In the FIG. 8 position the surfaces have moved equal distances to wherethe lines C13and D13 are aligned in the plane P. The mandrel has rotatedthrough while the presser roll has rotated In FIG. 9, each has rotatedin one-half of the cycle, as indicated at time t/2 in FIG. 5.

As already indicated, this difference in the extent of angular rotationof the presser roll relative to the mandrel at all times during acomplete cycle, except the four instances indicated by the intersectionof the curves in FIG. 5, and the change in angular velocity of thepresser roll during its rotation, are produced through rotation of thecasing 80 by the cam 92. The shape of the cam is such that when rotatedat the constant speed of the mandrel 12 it rocks or partially rotatesthe casing 80. When the casing is rotated in the same direction as theinput shaft 74, the angular velocity of the presser roll is less thanthat of the mandrel. This is indicated by those portions of the presserroll curve in FIG. 5 that have a smaller slope than that of the mandrelcurve at a given time. Conversely, when the casing is rotated in theopposite direction from the input shaft, the presser roll is rotated ata greater angular velocity than the mandrel. The periphery of the cam 92is contoured to reciprocate the rack 84 in accordance with the relativechange in radial length of the presser roll and mandrel, increasing thespeed of presser roll rotation as the radial length of the rolldiminishes relative to that of the mandrel in the plane P, anddecreasing the speed of presser roll rotation as the radial length ofthe presser roll increases relative to that of the mandrel. The preciseshape of the cam 92 depends of course upon the particular shape of themandrel and presser roll, but can be readily determined with suitableaccuracy by incrementally determining the relative angular velocityrequired of the presser roll to advance its periphery an increment equalto that advanced by the mandrel during a given time, provided that theincrements are small relative to the total peripheral length. By way ofexample only, 32 increments about a mandrel and presser roll each havingperimeters of approximately 7 inches were found satisfactory in thepresent embodiment for determining the relative velocities necessary tomaintain essentially equal peripheral speeds in a plane of mutualcontact.

In each of FIGS. 6 to 9, the constant distance between the axes of thepresser roll and mandrel is indicated by the lines F and G that passthrough the axes and are equidistant in each FIG. The actual distancebetween the axes A and B, as shown in FIGS. 6 to 9, is constant onlyuntil a sheet is wound about the mandrel 12. As a sheet is wound, thethickness of the sheet and each successive convolution requires asomewhat greater spacing between the axes. This is illustrated in FIG.10, which shows the axis B raised above the imaginary line F, by thethickness of the convolutions of the sheet S about the mandrel 12. Thedisplacement of the presser roll is accommodated by the presser arms 48,49 and the yieldable biasing force created by the fluid cylinders 62,67.

Referring now to FIGS. 1 to 3, it will be seen that the sheet S to bewound is supported during winding by the vacuum table 16, in the planeof the slot 21 of the mandrel, when the mandrel is oriented as shown inF IG. 2. The vacuum table is comprised of a plurality of vacuum boxes100, an end box 100a being located closely adjacent the winding mandrel12. All of the vacuum boxes have a flat, upper, surface 102 in a commonplane. The boxes are directly adjacent one another, side by side, aregenerally rectangular in shape, and extend substantially the length ofthe mandrel to provide a support for the sheet being wound. Oppositeends of the boxes are secured to a common support 104 at one end and 105at the other end. Each support has a tubular aperture 106, 107,respectively and is received on a horizontal mounting rod (not shown).In general, it is not necessary that the entire support length of thevacuum boxes be constructed to create a pressure differential betweenthe upper and lower surfaces of the sheet being supported, and for thatreason only a limited area of each box is provided with apertures 108 inthe flat upper surface 102. The end of each box supported by the support105 communicates through an opening 109 in the lower surface, to acoupling 110 and an exhaust conduit 1 l 1. The boxes are preferablyobstructed at the opposite side of the apertured portion from theopenings 109, by blocks 112. An additional vacuum box 1 14 is provided,that is movable in a direction parallel to the mandrel, and is used totransport a sheet of paper to be wound from a receiving positionadjacent the end 104 of the vacuum boxes, onto the vacuum boxes, and atthe same time sliding one edge of the sheet along the slot 21 of themandrel, so that the sheet is engaged in the winding mandrel whenpositioned. The movable vacuum box is separately connected with aflexible conduit to the source of reduced pressure. When a vacuum isapplied to the table through the conduits 111, the reduced pressurebeneath a portion of the sheet supported on the vacuum boxes retardsmovement of the sheet, which must slide across the boxes during winding,and thereby places the sheet in tension as it is wound.

To summarize the operation of the apparatus, a sheet S to be wound intoa tube of noncircular cross sectional shape is fed along the supportframe in a direction parallel to the mandrel 12, onto the vacuum table16. At the same time, one end of the sheet is inserted into the mandrelslot and gripped by the clamping jaw 22. A vacuum is applied to thetable 16 to resist movement of the sheet relative to the table duringwinding and fluid pressure is applied to the cylinders 62, 67 to biasthe presser roll 14 against the mandrel 12. The mandrel and presser rollare then driven in opposite directions by,the electric motor 34 andthrough a plurality of revolutions at relative angular velocities thatdiffer in accordance with the slopes of the curves of F IG. 5. As thesheet is wound, adhesive is applied to the upwardly facing surface ofthe unwound portion as it passes beneath the spray or quasi-sprayapplicator 17. During rotation, the presser roll 14 continuously pressesagainst the convolutions of the sheet that are wound about the mandrel.This pressure is applied progressively over the entire surface, withoutoscillation of the presser roll axis and with little or no slippagebetween the presser roll and sheet. As the sheet S is progressivelywound about the mandrel, the axis of the presser roll is gradually movedfarther away from the axis of the mandrel by the increased thickness ofthe tube wall being formed. This movement of the presser roll away fromthe mandrel is yieldably resisted by the fluid pressure of the cylinders62, 67. The biasing force of the fluid pressure plus the absence ofoscillation of the presser roll assures that the pressure exerted by thepresser roll upon the sheet being wound is continuous. Further, anyefiective increase in surface speed of the tube being wound by virtue ofthe increased radius created as convolutions are added will tend only toincrease the peripheral speed of the tube surface relative to thepresser roll, so that at no time is the presser roll rotating at agreater peripheral speed than the mandrel at the point of contact withthe tube, which would tend to loosen the convoluted plies. When thesheet has been completely wound about the mandrel l2, rotation of themandrel and presser roll is stopped by either deenergizing the motor 34or declutching the drive. Fluid to the cylinders 62, 67 is reversed andthe presser roll is raised from the mandrel and wound tube. The clampinggrip on the leading end of the sheet engaged by the mandrel is releasedand a finger is moved along the mandrel, sliding the wound tube eitheroff the mandrel or to an axially displaced portion of the mandrel forcuring, and is returned. Another sheet is then moved onto the table 16,gripped by the mandrel, and the cycle is repeated.

As will be evident from the described embodiment of this invention, animproved winding mechanism has been provided in which a tube ofnon-circulqr cross sectional shape can be convolutely wound at highspeeds while substantially uniform continuous pressure is appliedagainst the convolutions by a presser roll rotating at a peripheralspeed equal to that of the winding mandrel at the location of contactwith a sheet being wound to improve interply bonding and shape retentionand thereby provide an improved product capable of being manufactured athigh production rates. While a preferred embodiment of this invention asbeen described in detail, it will be apparent that various modificationsor alterations may be made therein, without departing from the spiritand scope of the invention set forth in the appended claims. Forexample, it will be appreciated that mechanisms of differentconstruction and operation than the differential mechanism describedherein can be used to accomplish the phase shift or change the angularvelocity of the presser roll relative to the mandrel, and tubes ofdifferent cross sectional shapes, such as rectangular shapes, can bewound in the same manner as described herein, using a mandrel andfollower roll of suitable shapes and an appropriately contoured controlcam. It will also be apparent that tubes can be wound in the mannerdisclosed herein from a plurality of separate sheets, with any sheetsubsequent to the first being secured at its leading end as well asthroughout its surface by adhesive, or the apparatus can be used toforma cover ply into a tubular shape. For example, a separate sheet can beapplied as a label to a wound tube or to a container received on themandrel for labeling.

I claim:

1. In apparatus for forming a sheet into a tubular shape noncircular incross section: an elongated rotatable mandrel having a non-circularshape in cross section; an elongated rotatable presser roll adapted tobe oriented parallel and located adjacent to the mandrel and having anon-circular shape in cross section different from that of said mandrel;the shape of said presser roll being such that, when in surface tosurface contact with the mandrel and when rotated at a varying angularvelocity that establishes a surface velocity in the area of mutualsurface contact equal to that of the mandrel when the mandrel is rotatedat a constant speed, the axis of the presser roll will remainessentially stationary.

2. In apparatus for convolutely winding a sheet into a tubular shapenon-circular in cross section: an elongated mandrel having a noncircularshape in cross section: means supporting said mandrel for rotation aboutits central longitudinal axis; means to rotate said mandrel about saidaxis; an elongated presser roll having a non-circular shape in crosssection different from that of said mandrel; means supporting saidpresser roll for rotation about its longitudinal axis and with itslongitudinal axis parallel to and adjacent the axis of said mandrel; theshapes of said mandrel and presser roll being such that the combineddistance from said axes to the respective adjacent surfaces of themandrel and presser roll, in the plane of the two axes, remains constantwhen both the mandrel and the presser roll are rotated in oppositedirections from a predetermined initial relationship at angularvelocities that establish essentially equal surface velocities in theplane of the two axes; and means to rotate at least one of said presserroll and mandrel at a varying angular velocity relative to the other toestablish essentially equal surface velocities thereof at a line ofcontact between the presser roll and either the mandrel or a sheet woundonto the mandrel.

3. Apparatus as set forth in claim 2 wherein said presser roll isrotated at a varying angular velocity relative to said mandrel.

4. Apparatus as set forth in claim 2 wherein said last-named meansincludes a phase changer with an input shaft rotatably driven at a speedproportional to that of said mandrel, a rotatable output shaft fordriving the presser roll, and means for varying the speed of said outputshaft relative to the input shaft in a predetermined relationship.

5. Apparatus as set forth in claim 4 including means supporting saidpresser roll for movement toward and away from said mandrel and meansyieldably biasing said presser roll toward said mandrel.

6. ln apparatus for forming a sheet into a tubular shape noncircular incross section: an elongated mandrel having a noncircular shape in crosssection; means supporting said mandrel for rotation about its centrallongitudinal axis; means to rotate said mandrel about said axis; anelongated presser roll having a non-circular shape in cross sectiondifferent from that of said mandrel; means supporting said presser rollfor rotation about its longitudinal axis and with its longitudinal axisparallel to the axis of said mandrel; said mandrel and presser rollbeing shaped so that the radial distance from the axis to the surface ofeach, considered in the plane of the two axes, varies inversely withrespect to that of the other, and the combined distances remainconstant, when both the mandrel and the presser roll are rotated inopposite directions and in predetermined timed relationship from apredetermined initial relationship; and means to rotate at least one ofsaid presser roll and mandrel at an increasing angular velocity whensaid radial distance decreases and at a decreasing angular velocity whensaid radial distance increases.

7. ln apparatus for forming a sheet into a tubular shape noncircular incross section: an elongated mandrel having a noncircular shape in crosssection; means supporting said mandrel for rotation about its centrallongitudinal axis; means to rotate said mandrel about said axis; anelongated presser roll having a non-circular shape in cross sectiondifferent from that of said mandrel; means supporting said presser rollfor rotation about its longitudinal axis and with its longitudinal axisparallel to the axis of said mandrel; the shapes of said mandrel andpresser roll being such that the combined distance from the centrallongitudinal axes to the respective adjacent surfaces of both, in theplane of the two axes, remains constant when both the mandrel and thepresser roll are rotated in opposite directions from a predeterminedinitial relationship at angular velocities that establish essentiallyequal surface velocities in the plane of the two axes; means to rotateat least one of said presser roll and mandrel at a varying angularvelocity relative to the other to establish essentially equal surfacevelocities thereof at a line of contact between the presser roll andeither the mandrel or a sheet wound onto the mandrel; a vacuum tableadjacent said mandrel for supporting a sheet being wound on the mandreland for retarding movement of the sheet during winding; means for movinga sheet to be wound onto said vacuum table; and means adjacent saidvacuum table for applying adhesive to said sheet as the sheet is woundonto said mandrel.

8. In a method of convolutely winding a sheet of paper or the like intoa tubular shape of non-circular cross section, the steps comprising:securing an end of a sheet in fixed relationship to an elongated mandrelof non-circular cross sectional shape that is rotatable about itscentral longitudinal axis, biasing an elon atedpresser rollthat isparallel to the mandrel and rotatable a ut its longitudinal axis againstsaid sheet as the sheet is wound, said presser roll and mandrel beingshaped so that the combined distance from the axes to the adjacentsurfaces of both in the plane of the two axes remains constant when bothare rotated in opposite directions from a predetermined initialrelationship at angular velocities that establish essentially equalsurface velocities in the plane of the two axes, rotating said roll andmandrel in opposite directions and at relatively varying angularvelocities that continuously establish equal surface velocities of thepresser roll and mandrel in the plane of the two axes at the line ofcontact between the roll and the tube, and maintaining continuouscontact between the tube being wound and the presser roll essentiallywithout relative osillation between said two axes.

9. A method as set forth in claim 8 including the step of spraying aquick-setting adhesive on an upwardly facing surface of said sheet asthe sheet is wound onto the mandrel.

10. A method as set forth in claim 8 including the step of supporting anunwound portion of the sheet on a vacuum table while the sheet is beingwound and tensioning the sheet during winding by decreasing the ambientpressure beneath the sheet.

11. A method as set forth in claim 9 including the step of supporting anunwound portion of the sheet on a vacuum table while the sheet is beingwound and tensioning the sheet during winding by decreasing the ambientpressure beneath the sheet.

1. In apparatus for forming a sheet into a tubular shape noncircular incross section: an elongated rotatable mandrel having a non-circularshape in cross section; an elongated rotatable presser roll adapted tobe oriented parallel and located adjacent to the mandrel and having anon-circular shape in cross section different from that of said mandrel;the shape of said presser roll being such that, when in surface tosurface contact with the mandrel and when rotated at a varying angularvelocity that establishes a surface velocity in the area of mutualsurface contact equal to that of the mandrel when the mandrel is rotatedat a constant speed, the axis of the presser roll will remainessentially stationary.
 2. In apparatus for convolutely winding a sheetinto a tubular shape non-circular in cross section: an elongated mandrelhaving a non-circular shape in cross section: means supporting saidmandrel for rotation about its central longitudinal axis; means torotate said mandrel about said axis; an elongated presser roll having anon-circular shape in cross section different from that of said mandrel;means supporting said presser roll for rotation about its longitudinalaxis and witH its longitudinal axis parallel to and adjacent the axis ofsaid mandrel; the shapes of said mandrel and presser roll being suchthat the combined distance from said axes to the respective adjacentsurfaces of the mandrel and presser roll, in the plane of the two axes,remains constant when both the mandrel and the presser roll are rotatedin opposite directions from a predetermined initial relationship atangular velocities that establish essentially equal surface velocitiesin the plane of the two axes; and means to rotate at least one of saidpresser roll and mandrel at a varying angular velocity relative to theother to establish essentially equal surface velocities thereof at aline of contact between the presser roll and either the mandrel or asheet wound onto the mandrel.
 3. Apparatus as set forth in claim 2wherein said presser roll is rotated at a varying angular velocityrelative to said mandrel.
 4. Apparatus as set forth in claim 2 whereinsaid last-named means includes a phase changer with an input shaftrotatably driven at a speed proportional to that of said mandrel, arotatable output shaft for driving the presser roll, and means forvarying the speed of said output shaft relative to the input shaft in apredetermined relationship.
 5. Apparatus as set forth in claim 4including means supporting said presser roll for movement toward andaway from said mandrel and means yieldably biasing said presser rolltoward said mandrel.
 6. In apparatus for forming a sheet into a tubularshape non-circular in cross section: an elongated mandrel having anon-circular shape in cross section; means supporting said mandrel forrotation about its central longitudinal axis; means to rotate saidmandrel about said axis; an elongated presser roll having a non-circularshape in cross section different from that of said mandrel; meanssupporting said presser roll for rotation about its longitudinal axisand with its longitudinal axis parallel to the axis of said mandrel;said mandrel and presser roll being shaped so that the radial distancefrom the axis to the surface of each, considered in the plane of the twoaxes, varies inversely with respect to that of the other, and thecombined distances remain constant, when both the mandrel and thepresser roll are rotated in opposite directions and in predeterminedtimed relationship from a predetermined initial relationship; and meansto rotate at least one of said presser roll and mandrel at an increasingangular velocity when said radial distance decreases and at a decreasingangular velocity when said radial distance increases.
 7. In apparatusfor forming a sheet into a tubular shape non-circular in cross section:an elongated mandrel having a non-circular shape in cross section; meanssupporting said mandrel for rotation about its central longitudinalaxis; means to rotate said mandrel about said axis; an elongated presserroll having a non-circular shape in cross section different from that ofsaid mandrel; means supporting said presser roll for rotation about itslongitudinal axis and with its longitudinal axis parallel to the axis ofsaid mandrel; the shapes of said mandrel and presser roll being suchthat the combined distance from the central longitudinal axes to therespective adjacent surfaces of both, in the plane of the two axes,remains constant when both the mandrel and the presser roll are rotatedin opposite directions from a predetermined initial relationship atangular velocities that establish essentially equal surface velocitiesin the plane of the two axes; means to rotate at least one of saidpresser roll and mandrel at a varying angular velocity relative to theother to establish essentially equal surface velocities thereof at aline of contact between the presser roll and either the mandrel or asheet wound onto the mandrel; a vacuum table adjacent said mandrel forsupporting a sheet being wound on the mandrel and for retarding movementof the sheet during winding; means for moving a sheet to be wOund ontosaid vacuum table; and means adjacent said vacuum table for applyingadhesive to said sheet as the sheet is wound onto said mandrel.
 8. In amethod of convolutely winding a sheet of paper or the like into atubular shape of non-circular cross section, the steps comprising:securing an end of a sheet in fixed relationship to an elongated mandrelof non-circular cross sectional shape that is rotatable about itscentral longitudinal axis, biasing an elongated presser roll that isparallel to the mandrel and rotatable about its longitudinal axisagainst said sheet as the sheet is wound, said presser roll and mandrelbeing shaped so that the combined distance from the axes to the adjacentsurfaces of both in the plane of the two axes remains constant when bothare rotated in opposite directions from a predetermined initialrelationship at angular velocities that establish essentially equalsurface velocities in the plane of the two axes, rotating said roll andmandrel in opposite directions and at relatively varying angularvelocities that continuously establish equal surface velocities of thepresser roll and mandrel in the plane of the two axes at the line ofcontact between the roll and the tube, and maintaining continuouscontact between the tube being wound and the presser roll essentiallywithout relative osillation between said two axes.
 9. A method as setforth in claim 8 including the step of spraying a quick-setting adhesiveon an upwardly facing surface of said sheet as the sheet is wound ontothe mandrel.
 10. A method as set forth in claim 8 including the step ofsupporting an unwound portion of the sheet on a vacuum table while thesheet is being wound and tensioning the sheet during winding bydecreasing the ambient pressure beneath the sheet.
 11. A method as setforth in claim 9 including the step of supporting an unwound portion ofthe sheet on a vacuum table while the sheet is being wound andtensioning the sheet during winding by decreasing the ambient pressurebeneath the sheet.